ORDINARY PORTLAND-CEMENT BASED SOLIDIFICATION OF TOXIC WASTES - THE ROLE OF OPC REVIEWED

A mixed waste stream, which is commercially solidified, has been solidified in the laboratory using OPC and PFA in a variety of mix proportions. The solidified products have been subjected to calorimetric, physical and microstructural analysis. The heat of hydration for OPC/waste mixes showed that a progressive poisoning of normal hydration reactions occurred with increasing waste addition. Once poisoned OPC failed to act as a cement and was substituted by PFA and other products in this role. Strength development was found to be related to the heat of hydration; this suggests that conduction calorimetry could be used to determine the suitability of a particular waste for OPC based solidification.